The Features of Refraction of Electromagnetic Waves Near the Electron Cyclotron Resonance Surface in an Open Magnetic Trap

Some features of the electromagnetic wave propagation near the electron cyclotron resonance region in axisymmetric magnetic traps are studied both analytically and numerically. The ray paths are obtained with allowance for the plasma density inhomogeneities, magnetic field direction, and magnetic field strength. Criteria for the limiting cases of constructive refraction (the ray paths are attracted to the trap axis, where effective absorption takes place) and destructive refraction (the ray paths are expelled from the trap axis, and efficient heating of the central part of the plasma column is not possible) are found. It is shown that the inhomogeneities of the magnetic field direction and plasma density, which are typical of axisymmetric magnetic traps, as well as the spatial dispersion effects, can strongly affect the electromagnetic wave propagation near the electron cyclotron resonance surface.